Field of the Invention
The present invention relates to a stent delivery system for placing a stent into a hollow region included in the alimentary system, the respiratory system, the urinary system, the reproduction system or the like.
Description of the Related Art
In a case where a stricture or an obstruction arises somewhere in a hollow organ included in the alimentary system, the respiratory system, the urinary system, the reproduction system or the like, in order to recover the real function of the hollow organ, a path is ensured in the hollow organ by placing a stent into the stricture or obstruction. Recently, the operation for placing a stent into a diseased part of the hollow organ which requires treatment is commonly performed using an endoscope and exclusive instruments. For example, in the document of U.S. Pat. No. 5,921,952, a stent delivery system used in the above-mentioned operation is disclosed. In particular, the system includes a guide catheter, a guide wire, a push catheter, and a suture for detachably connecting a stent to a tip of the push catheter. The guide catheter is inserted into the inside of the stent, and inserted into the interior of the living body with the stent. The guide wire guides the guide catheter and the stent to the interior of the living body so as to be inserted into the inside of the guide catheter. The push catheter is inserted into the interior of the living body with the guide catheter in a state where the guide catheter is inserted into the inside of the push catheter, and is used for pushing the stent along the guide catheter. Both ends of the suture are tied to each other, in a state where the suture is laced through a hole formed at a head section of the push catheter. Further, a part of the suture is inserted into the inside of the stent through a hole formed at the stent, and forms a loop. Since a head section of the guide catheter is inserted into the loop, the suture is not separated from the stent. That is, the stent is detachably connected with the tip of the push catheter through the suture.
With the operation, first, the four members are joined as mentioned above, that is, the stent, the guide catheter, the push catheter and the suture are inserted into a channel of an endoscope along the guide wire, then the members are protruded from a tip of a insertion portion of the endoscope. The stent and the head section of the guide catheter are inserted into an affected part of a hollow organ which requires a procedure.
Next, in a state where the guide wire and the push catheter are held in place, the guide catheter is retracted by pulling it from the channel of the insertion portion of the endoscope. At this time, it is not always necessary to retract the entire guide catheter. When the guide catheter is pulled, the head section of the guide catheter is retracted away from the loop of the suture, accordingly the constraint of the stent by the guide catheter is eliminated. Next, similarly to the guide catheter, the guide wire is retracted by pulling the guide wire so as to retract it from the channel of the insertion portion of the endoscope. At this time, also it is not always necessary to retract the entire guide wire. When the guide wire is pulled, the tip of the guide wire is retracted away from the loop of the suture, accordingly the constraint of the stent by the guide catheter is eliminated. As a result, the engagement between the stent and the push catheter through the suture is separated.
Next, when the push catheter is pulled so as to retract it from the channel of the insertion portion of the endoscope, since the engagement between the stent and the push catheter has been separated already, only the stent is placed at the affected part of a hollow organ which requires a procedure.
With the operation as mentioned above, when the stent and the head section of the guide catheter are inserted into the affected part of a hollow organ which requires procedure, if the stent is placed at a position which is deeper than the affected part, the push catheter is pulled slightly before pulling the guide catheter or the guide wire, that is, before separating the engagement between the stent and the push catheter. Therefore, it is possible to replace the stent connected with the tip of the push catheter to the desired position.